1. Field of Invention
The present invention relates to a bump structure whose mounting position, shape, and size can be favorably controlled and to a method of manufacturing the same.
2. Description of Related Art
When an element is directly mounted onto a board using flip-chip bonding, in many cases, such mounting is carried out via bumps made of metal (metal bumps) formed on the element or on the electrodes of the board. As one example, these metal bumps can be formed by fusing metal wires and then breaking off the wires. See, for example, Japanese Unexamined Patent Publication No. H05-6893. Alternatively, these metal bumps can be formed by plating. See, for example, Japanese Unexamined Patent Publication No. H05-6893 and Japanese Unexamined Patent Publication No. H05-47768. However, such methods for forming metal bumps require complex processes and/or apparatuses. Also, it is difficult to control the shapes and sizes of the obtained metal bumps, as well as the formation positions of the metal bumps, with high precision.
On the other hand, a method that discharges conductive paste using an ink jet method is known as a simpler method for forming metal bumps. See, for example, Japanese Unexamined Patent Publication No. H03-60036. However, since the viscosity of conductive paste is normally extremely high, when this method of forming is used, it is difficult to precisely discharge the conductive paste from the nozzle of an ink jet head. This means that in the same way as the methods of forming described above, it is difficult to control the shapes and sizes of the formed metal bumps, as well as the formation positions of the metal bumps, with high precision.